An ultrasonic diagnostic apparatus is a diagnostic apparatus which acquires and displays an ultrasonic image of biological information. This apparatus is used as a useful apparatus which is inexpensive, free from radiation, and used for real time, noninvasive observation as compared with other image diagnostic apparatuses such as an X ray diagnostic apparatus and X ray computed tomography apparatus.
When performing ultrasonic diagnosis on a living body by using an ultrasonic diagnostic apparatus, the upper limit of the acoustic power of ultrasonic waves output from an ultrasonic probe is determined in consideration of safety standard. In order to observe this safety standard, this apparatus controls acoustic powers so as not to make the following parameters exceed their upper limits: Ispta (spatial peak temporal average intensity).3 which is the temporal average value of the highest intensities of sounds in an acoustic field, MI (Mechanical Index) which is an index associated with a mechanical action of ultrasonic waves on the living body, TI (Thermal Index) which is an index associated with the thermal action of ultrasonic waves on the living body, and TempRise (probe surface temperature rise).
In a mode constituted by a plurality of display modes, like a color mode, (to be referred to as a combination mode hereinafter), it is necessary to control acoustic powers in the respective display modes so as not to make the sums of values in the respective display modes exceed the upper limit values with respect to Ispta.3, Ti, and TempRise and not to make the maximum value of the values of MI in the respective display modes exceed the upper limit value.
Conventionally, it is possible to decrease the acoustic powers in the respective display modes of the above combination mode by operating the adjustment knobs provided on the ultrasonic diagnostic apparatus. However, the apparatus is not provided with any means for increasing the acoustic powers in the respective display modes from the viewpoint of preventing each parameter described above from exceeding the upper limit value. In addition, the default acoustic power output ratios in the respective display modes have been derived from the fixed ratios set in advance in a table or the like in the ultrasonic diagnostic apparatus. For this reason, the user cannot increase the sensitivity of a specific display mode by freely changing the acoustic power output ratios in the respective display modes.